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PubMed1996

[A case of effective decompression at the first segment of the vertebral artery for intractable vertigo].

Atherosclerotic change is the main reason for vertebrobasilar insufficiency. However, if clinical symptoms such as vertigo happen transiently and repeatedly with head movement, vascular insufficiency due to mechanical compression of the vertebral artery must be kept in mind as its cause. The patient was a 54-year-old male complaining of recurrent vertigo which occurred during head rotation. He had been treated medically before he came to our hospital. Right compressed vertebral angiogram with head turned to the right and left compressed vertebral angiogram with head turned to the left were obtained at the first segment. Unilateral decompression of the vertebral artery was performed. At surgery it was found that the right vertebral artery was compressed by a stellate ganglion. After cutting of the sympathetic chains, the stellate ganglion was detached from the vertebral artery. The patient's intractable vertigo immediately disappeared after this procedure. It is concluded that if severe vertigo or dizziness is repeated under certain conditions, we must perform a bilateral vertebral angiogram and differentiate whether it is a case of decompression or not and then take measures to bring about decompression effectively.

Humans↗
PubMed1995

[Decompressive neurovascular nose and skull-base surgery in primary headache with a rhinogenic trigger].

The therapeutical results such as recoveries or substantial improvements obtained by neurovascular decompressive functional morpho-corrective rhino-skull base surgery on 2124 cases of primary headaches (migraine with aura, migraine without aura, cluster headache, chronic paroxysmal hemicrania, tension-type headache) obliges a thorough review of the classical chapter on "rhinogenous headaches" (Bonaccorsi, Novak, Blondiau, Bisschop, Hoover, Clerico). In fact all those headaches seemingly "primary", but having a "central-peripheral" etiopathogenesis proved by a well documented (CT) volumetric reduction of "ethmoidosphenoidal subcribriform chamber" according to hemoangiokinetics purposes of endo-exocranial anastomotic circulation of this area, should be included in the chapter of "rhinogenous headaches". This endo-exocranial anastomotic circulation is considered a "functional unit" owing to the continuity of rhino-ophthalmic-encephalic trigeminal-vegetative and vascular circuits (Hannerz, Hardebo, Moskowitz). These morphological abnormalities of the rhino-skull base osteo-vascular-mucous structures acquire physio-pathological significance only in patients with "low pain threshold and elevated central integrative capability", modulated and timed by the neurogenic biorhythms. It is described the surgery of rhino-skull base by "neurovascular decompressive septo-ethmoidosphenoidectomy" procedure, either conservative or radical till the III grade monolateral with trigeminal and vegetative selective neurotomy that permits to save olfaction and to remove even the controlateral pain decompressing the circulation and eliminating stasis even on the opposite side. Further, it is emphasized that the neurological deficit or central irritative symptomatology (visual aura, sensory-motor paresis, epilepsy) disappears after surgical removal of the "peripheral rhinogenous trigger". It demonstrates a cause and effect relationship that is the central peripheral functional interdependence, even if it's included in the neuro-transmissive, biochemical, neuro-endocrine, constitutional background which is controlled by the psychical, vegetative and dysnociceptive biorhythms.

Edema↗
PubMed1995

[Ogilvie's syndrome. Benefits of repeat colonoscopic decompression on its developmental course].

Seven cases of Ogilvie's syndrome are described. In six of ther good recovery was related to repeated endoscopic colonic decompressions. This is the safest and most precise procedure in the diagnosis and treatment of the disease. We emphasize the usefulness of repeated decompressions in the outcome of Ogilvie's syndrome. One of patients in which decompression was not attempted died of a colonic rupture.

Aged↗
PubMed1996

Avascular necrosis of the talus treated by core decompression.

We reviewed 11 patients (17 ankles) who had had core decompression for symptomatic avascular necrosis of the talus before collapse. The Mazur grading system was used to assess function preoperatively and at final follow-up, and radiographs were graded according to the Ficat and Arlet (1980) classification modified for the ankle. At a mean follow-up of seven years (2 to 14) 14 ankles (82%) had an excellent or good outcome (Mazur scores > 80 points; pain scores > 40 points (41 to 50). The other three ankles required tibiotalar fusion at a mean of 13 months (5 to 20) after core decompression. We conclude that core decompression is a viable method of treatment for symptomatic avascular necrosis of the talus before collapse.

Adult↗
PubMed1996

Laser decompression of the facial nerve.

Laser decompression of the facial nerve is an experimental approach to evaluating the parameters for laser usage at a nerve-bone interface. This article summarizes the anatomic considerations and indications for facial nerve decompression, and the advantages and disadvantages of laser decompression of the facial nerve. Preliminary studies using the Vanderbilt free electron laser are described, and future directions for research are outlined.

Electrons↗
PubMed1996

[Stenosis of the lumbar spine in elderly persons. Surgical decompression].

The degenerative changes in the lumbar vertebral spine frequently appear as encroachment of the lumbar spinal canal. Degenerative changes of the anatomical structures dictate the location of the stenosis, which are divided in central or lateral stenosis of the lumbar spinal canal. According to this localization, more radicular symptoms in a lateral stenosis might be prevalent in contrast to the mixed symptoms of a central stenosis. Operative decompression might be indicated in cases with correlation of clinical symptoms and radiological findings. The operative treatment aims at a satisfactory decompression without creating iatrogenic instability. An additional fusion might be avoided in cases without apparent instability. Adequate operative decompression is most efficient concerning reduction of pain and increasing of walking distance.

Aged↗
PubMed1992

Numerical phase algorithm for decompression computers and application.

Present generation decompression computers employ a simplified algorithm, limiting dissolved gas build-up in tissue and blood according to a method proposed by Haldane 80 years ago. Such a model works well for single dives, but is usually liberal and theoretically incomplete for multiple exposures within 24 hr spans. Using the critical phase hypothesis in a bubble model, we have extended the classical model of Haldane to multi-exposures. This model is discussed, and a decomputer algorithm described for multi-diving. The focus is permissible bubble excess, not just dissolved gas per se, with phase constraints affecting all tissues, fast and slow, and requiring a systematic lowering of repetitive tissue tensions. Deep repetitive and shallow multi-day exposures are impacted most by the procedure. Within nucleation theory deeper-than-first dives are also treated. A set of multi-diving fractions, xi, accounting for micronuclei excitation and regeneration, reduced bubble elimination in repetitive activity, and coupled effects on tissue tension, are proposed, with xi representing a set of multiplicative factors (less than one) applied to critical tissue tensions for multi-exposures. These factors affect repetitive activity over short time spans, deeper-than-previous and continuous multi-day activities, compared to standard computer software, and are easily encoded into existing decompression meters, potentially extending their range and flexibility over exposure regimes.

Algorithms↗
PubMedDate not supplied

Subatmospheric decompression: neurological and behavioural studies.

Several studies in animals over the past decade have shown that prolonged exposures to pressures within the range 226 mm Hg to 160 mm Hg (30,000 to 37,500 ft) are likely to lead to brain damage. This often results in neurological and behavioural disturbance, which may be subtle and reversible or gross and ultimately fatal. The appearance of these impairments is often delayed until several hours or even days after exposure. Immediate survival does not necessarily ensure recovery. In contrast, decompression to pressures below 160 mm Hg or above 226 mm Hg are unlikely to have adverse effects if the exposure is survived. The most probable outcomes of such decompressions are death or uneventful recovery.

Aerospace Medicine↗
PubMed2002

The fellow eye in NAION: report from the ischemic optic neuropathy decompression trial follow-up study.

PURPOSE: To examine the prevalence and incidence of second eye nonarteritic anterior ischemic optic neuropathy (NAION) and associated patient characteristics in patients enrolled in the Ischemic Optic Neuropathy Decompression Trial (IONDT) Follow-up Study. DESIGN: Randomized clinical trial with observational cohort. METHODS: Patients randomized to optic nerve sheath decompression surgery or careful follow-up had a diagnosis of acute unilateral NAION, visual acuity between 20/64 and light perception, and were aged 50 years or older. Eligible patients who declined randomization or whose visual acuity was better than 20/64 were not randomized but followed as part of an observational cohort. Follow-up examinations took place at 3, 6, 12, 18, and 24 months and annually thereafter. RESULTS: Four hundred eighteen patients were enrolled; 258 randomized and 160 observed. Previous NAION or other optic neuropathy was present in the fellow eye of 21.1% (88/418) of patients at baseline. Four patients developed optic neuropathy in the fellow eye at follow up that could not be conclusively diagnosed as NAION. New NAION in the fellow eye occurred in 14.7% (48/326) of patients at risk during a median follow up of 5.1 years. Randomized patients experienced a higher incidence (35/201; 17.4%) than nonrandomized patients (13/125; 10.4%). A history of diabetes and baseline visual acuity of 20/200 or worse in the study eye, but not age, sex, aspirin use, or smoking were significantly associated with new NAION in the fellow eye. Final fellow eye visual acuity was significantly worse in those patients with new fellow eye NAION whose baseline study eye visual acuity was 20/200 or worse. CONCLUSIONS: Follow-up data from the IONDT cohort provide evidence that the incidence of fellow eye NAION is lower than expected: new NAION was diagnosed in 14.7% of IONDT patients over approximately 5 years. Increased incidence is associated with poor baseline visual acuity in the study eye and diabetes, but not age, sex, smoking history, or aspirin use.

Acute Disease↗
PubMed1984

Latency in onset of decompression sickness on direct ascent from air saturation.

Twenty-four human subjects were exposed to compressed air at simulated depths ranging from 45 ft seawater gauge (fsw) (2.36 ATA) to 75 fsw (3.27 ATA) for periods of time sufficient to allow saturation of most tissues with inert gas. From each of four depths (45, 55, 65 and 75 fsw), subjects ascended directly to 1 ATA, where they remained for 30, 17, 13, and 10 min, respectively. During this time the onset of Doppler detected venous gas emboli (VGE), pruritus, and any other symptomatology was monitored and recorded. In the ascending excursion from 45 fsw (n = 18), the mean appearance times of pruritus and VGE were 19.3 +/- 7.5 (mean +/- SD) and 21.9 +/- 7.4 min, respectively, with one case of pain-only decompression sickness (DCS). The excursion from 55 fsw (n = 17) shortened these times to 9.2 +/- 3.3 and 14.4 +/- 3.2 min, respectively, with two cases of DCS, one each of pain-only and serious types. In the excursion from 65 fsw (n = 23), mean pruritus and VGE appearance times were 6.3 +/- 1.4 and 10.8 +/- 1.9 min, respectively, with no cases of DCS. The excursion from 75 fsw (n = 6) resulted in appearance times of 4.8 +/- 0.8 and 8.2 +/- 1.2, respectively, with one case of pain-only DCS. Sufficient cases of DCS did not occur in any of the excursions to allow determination of mean appearance times. The relationship between pressure reduction and appearance times of pruritus and VGE, and the threshold time of DCS, can be described mathematically. We conclude that latency in the development of DCS on direct ascent from air saturation exists and is of sufficient magnitude to permit practical application in emergency decompressions or unpressurized transfers between compressed air or N2-O2 environments.

Adult↗
PubMed2001

Increasing activity of H(2)-metabolizing microbes lowers decompression sickness risk in pigs during H(2) dives.

The risk of decompression sickness (DCS) was modulated by varying the biochemical activity used to eliminate some of the hydrogen (H(2)) stored in the tissues of pigs (19.4 +/- 0.2 kg) during hyperbaric exposures to H(2). Treated pigs (n = 16) received intestinal injections of Methanobrevibacter smithii, a microbe that metabolizes H(2) to water and CH(4). Surgical controls (n = 10) received intestinal injections of saline, and an additional control group (n = 10) was untreated. Pigs were placed in a chamber and compressed to 24 atm abs (20.6-22.9 atm H(2)). After 3 h, the pigs were decompressed and observed for symptoms of DCS for 1 h. Pigs with M. smithii had a significantly lower (P < 0.05) incidence of DCS (44%; 7/16) than all controls (80%; 16/20). The DCS risk decreased with increasing activity of microbes injected (logistic regression, P < 0.05). Thus the supplemental tissue washout of the diluent gas by microbial metabolism was inversely correlated with DCS risk in a dose-dependent manner in this pig model.

Animals↗
PubMed1980

Induced vestibular dysfunction in squirrel monkeys during rapid decompression.

The symptoms of postural instability and dizziness associated with decompression sickness could be ascribed to either damage of the vestibular apparatus or to central nervous system damage. However, a histological study of monkeys exposed to decompression reveals that these symptoms primarily result from damage to the vestibular apparatus (unless there are accompanying central deficits). Furthermore, the damage is of a type that causes new bone growth to occlude the otic fluid spaces of the semicircular canals. In some instances, there is sufficient bone growth to render the cristae ampullares as non-functional end organs. Such diminished vestibular function would present a serious threat to the diver.

Animals↗
PubMedDate not supplied

Semicircular canal fractures in squirrel monkeys resulting from rapid decompression. Interpretation and significance.

A recent histological study of monkeys rapidly decompressed from deep dives has revealed that, in some cases, there are fractures of the bone surrounding the semicircular canals. In some monkeys sacrificed within a few days of their dives, there are full thickness breaks across the bony canal walls. In others, sacrificed several months after a dive, these fractures have become infiltrated by the ectopic growth of new bone which also invades the otic fluid spaces. It now appears that the new bone growth is caused not only by a ripping or irritation of the endosteum, which lines the inside of the bony canals, but also, at least in some cases, by a rupturing of the very hard petrous bone itself. It is difficult to avoid the conclusion that, somehow, large forces are developed within the inner ear or within the petrous bone during decompression.

Animals↗
PubMed2000

Lack of effect of anti-C5a monoclonal antibody on endothelial injury by gas bubbles in the rabbit after decompression.

Previous studies have shown that gas bubbles activate the complement system in vitro, generating C5a. The effect of anti-C5a monoclonal antibody 4B1C11 in preventing endothelial damage caused by decompression in the pulmonary artery of the rabbit was examined. The endothelial response was measured using tension measurements in the blood vessel wall. The mean bubble count for all rabbits (n = 24) was 4.2+/-3.1 bubbles x cm(-2), and ranged from 0 to 15 bubbles x cm(-2). Animals with many bubbles showed significantly more vascular damage than those with fewer bubbles. Anti-C5a monoclonal antibody could not prevent endothelial damage than that occurred after exposure to this level of gas bubbles. The maximum number of gas bubbles present is important for the endothelial damage. We speculate that the endothelial damage observed was mainly mechanical. A possible beneficial effect of anti-C5a antibody can thus be masked at a high degree of bubble generation. This study, together with a previous paper, demonstrates that gas bubbles cause endothelial damage from decompression both in the pig and in the rabbit.

Acetylcholine↗
PubMed2001

Decompression sickness risk reduced by native intestinal flora in pigs after H2 dives.

Decompression sickness (DCS) risk following a simulated dive in H2 was lower in pigs with a native intestinal flora that metabolized H2. Pigs (n = 27; 19.4 +/- 0.2 kg body mass) were placed in a chamber that was pressurized to 22.2-25.5 atm (absolute; 2.2-2.6 MPa) with 84-93% H2 for 3 h. Chamber concentrations of O2, H2, He, N2, and CH4 were monitored by gas chromatography. Release of CH4 from the pigs indicated that intestinal microbes had metabolized H2 After decompressing to 11 atm, the pigs were observed for DCS. Animals with DCS released significantly less (P < 0.05) methane (0.53 +/- 0.37 ppm CH4; n = 5) than those without DCS (1.40 +/- 0.17 ppm CH4; n = 22). The DCS risk reduction was attributed to the loss of roughly 12% of the total volume of H2 that could be stored in the tissues of the pigs. Thus, H2 metabolism by the native intestinal flora of pigs may protect against DCS following a simulated H2 dive.

Animals↗
PubMed2005

Bubble incidence after staged decompression from 50 or 60 msw: effect of adding deep stops.

OBJECTIVES: The French Navy uses the Marine Nationale 90 (MN90) decompression tables for air dives as deep as 60 msw. The resulting incidence of decompression sickness (DCS) for deep dives (45-60 msw) is one case per 3000 dives. METHODS: Three protocols with experimental ascent profiles (EAPs) were tested in the wet compartment of a hyperbaric chamber. For each protocol, eight subjects dove to 50 or 60 msw and ascended according to the standard MN90 table or an EAP. Precordial bubbles were monitored with Doppler sensors at 30-min intervals after surfacing. Protocol I went to 60 msw and used deep stops beginning at 27 msw. Protocol II was a repetitive dive to 50 msw with a 3-h surface interval; the EAP made the first deep stop at 18 msw. Protocol III again went to 60 msw, but the EAP used a single, shorter deep stop at 25 msw. RESULTS: For Protocol I, all divers developed bubbles at Spencer grade 2-3 and still had bubbles 120 min after surfacing; there was no statistical difference between bubbling for the MN90 and EAP, but one diver presented a case of DCS after the EAP. For Protocol II, the EAP produced severe bubbling for the eight divers. Those findings led to stopping the EAPs with the longer deep stops used in Protocols I and II. Protocol III again showed no difference between the standard and modified profiles. DISCUSSION: The addition of deep stops requires careful consideration. Two of our EAPs made no difference and one produced increased bubbling.

Adult↗
PubMedDate not supplied

Decompression illness presenting as breast pain.

We present two cases of decompression illness in women in whom the initial symptom causing distress after completion of the dives was breast pain. Both women were also subsequently found to have a patent foramen ovale. We postulate that breast pain may be an unusual under-recognized manifestation of decompression illness.

Adult↗
PubMed1990

Acute decompression sickness in compressed air workers exposed to pressures below 1 bar in the Singapore Mass Rapid Transit project.

The Singapore Mass Rapid Transit (MRT) project started compressed air work in Oct 1984. Eleven km of underground tunnels out of 20 km were built using this method. Cases of decompression sickness (DCS) arising from compressed air work are rare with working pressures less than 1 bar gauge. However, there were 10 cases of DCS in the MRT project who were exposed to less than 1 bar pressure. The authors present their clinical features and attempt to explain the observations in relation to theories of bubble nuclei formation, gas loading and rate of decompression. The formation of bubble micronuclei are correlated with physical factors like heavy exertion, and the use of vibrating tools. The concept of extremely long tissue half-times in the absorption of nitrogen in the body is discussed as a contributory factor to the development of DCS under 1 bar.

Acute Disease↗